


When It Happens

by byesweetheart (ConstantComment)



Category: Haikyuu!!
Genre: Alpha/Beta/Omega Dynamics, Best Friends, Coming of Age, Friends to Lovers, Gender Roles, Internalized Misogyny, LITERALLY, Lots of spontaneous orgasms basically, M/M, Omega Verse, Rough Sex, Scent Kink, Scent Marking, Scenting, Trope Subversion, parallels to homophobia
Language: English
Status: Completed
Published: 2017-11-24
Updated: 2017-11-24
Packaged: 2019-02-06 07:59:15
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, Underage
Chapters: 1
Words: 3,586
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12813114
Author URL: https://archiveofourown.org/users/ConstantComment/pseuds/byesweetheart
Summary: Things are a little wobbly in their friendship for a month after the day of their tournament win. Not really because of the way it happened—although thinking about it makes Oikawa’s stomach do exactly the same thing it did on the court, makes his mouth water again—but, because Iwaizumi is presented now. He’s of age, he’s eligible, he’s an Alpha, and Oikawa… isn’t anything yet.





	When It Happens

**Author's Note:**

> **Day 19: Scent**
> 
>  
> 
> I don’t know how I managed this... but I think the A/B/O trope made these two... more gay. Double-gay. So, enjoy that.

Oikawa is fourteen when it happens. He’d say ‘when it happens to Iwa-chan,’ but that just isn’t accurate enough. It happens to both of them. It happens.

When it happens, they’re on the court (as with most things when it comes to them). They just won an exhausting game. It went too long, after a too long tournament day, after weeks of practices where they were working so hard you could almost feel the tension in the air, the sharp-edged knuckles of clenched hands, the tang of sweat and the stumble of barely caught breaths as they worked toward their goal.

Iwaizumi hunches over in his spot by the net and pants as the losing team tries to hold back tears, and Oikawa eyes the high school scout who nods at their coach from the stands. He sighs happily, confident they’ll both definitely be accepted into Seijoh now. He and Iwaizumi are the strongest players in the gym right now—maybe _especially_ Iwaizumi who made almost all their points with a sudden and relentless, almost _angry_ determination in their last set.

Oikawa calls to him, wipes his forehead as he jogs over, and as soon as he reaches him he catches a scent. It’s a little cloying, a little earthy, and a lot jumbled up in his stomach when he jams his fingers into Iwaizumi’s hair like always and gives it a quick ruffle.

The boy groans and lifts himself from leaning on his knees. His arm reaches out to grab at Oikawa clumsily like he’s fighting a dizzy spell, like he’s spent ten minutes with his head hanging off the edge of the bed while Oikawa plays FIFA and all the blood is rushing away as he sits up. Oikawa always laughs when that happens, because Iwaizumi has the _best_ expressions.

But this seems different. He has a hand in Oikawa’s sweaty jersey in seconds, curling into him like… like a hug, but then he’s coming closer. He looks cross-eyed. He looks confused and lost, not like a _winner_. He stumbles into Oikawa’s side and nudges his face under his jaw until his nose is tucked right up under his ear. And he _scents_ him. Just—in front of everyone! With a rumbling, tortured noise that makes Oikawa’s stomach clench.

You don’t just _do_ that to someone.

They haven’t done it for a little while, not since they were coming out of elementary and their parents sat them each down for The Talk. Oikawa giggles nervously as his mind flashes to his living room couch, to Iwa-chan’s ruddy knees before he left their playdate that day and his father came and sat with him, gave him a book on Mating with scary diagrams and pictures that made Oikawa blush.

Oikawa pretends his mouth doesn’t water from the scent clouding around them, pretends he doesn’t have an inkling of what it could mean, like that book said years ago. Instead, he says, “Iwa-chan—”

And Iwaizumi gasps against his neck, knees buckling.

Their coach, and Iwaizumi’s mother in the stands, call out to them, finally noticing how far Iwaizumi’s scent has traveled and how he has, in seconds that felt like minutes to Oikawa, changed.

His hips slide against Oikawa as he slips a little toward the floor, and Oikawa can feel it.

He can feel him spilling, shaking, as he pops his first knot against Oikawa’s leg.

Things are a little wobbly in their friendship for a month after the day of their tournament win. Not _really_ because of the way it happened—although thinking about it makes Oikawa’s stomach do _exactly_ the same thing it did on the court, makes his mouth water again—but, because Iwaizumi is presented now.

He’s of age, he’s eligible, he’s an _Alpha,_ and Oikawa… isn’t anything yet.

Phone calls become more regular than meet-ups in the park when they’re outside of class, until things swing back to normal once Iwaizumi’s hormones calm and he has a heat management plan approved by their school.

Iwaizumi never scents him again.

When Oikawa presents on a boring Sunday nearly a year later, just doing chores in the yard, he’s almost disappointed when he comes to and finds he’s rutted himself unconscious on a pile of leaves next to the rake, knotted in his jeans.

All those moments under his covers in the dark, thinking about how he could be with Iwa-chan forever if he had just been an Omega, sting particularly badly in his eyes as he sways his way up to his bedroom to be found later in a heap of blankets by his parents.

He expects… Well, Oikawa is not quite sure what he expects when he sees Iwaizumi next, maybe they’d see each other and Oikawa’s stomach wouldn’t twist around itself, his eyes wouldn’t dart to Iwaizumi’s mouth, his neck, maybe he’d just find a dull happiness where the longing was before but that’s definitely not what happens.

Oikawa is shoving a bag of his soiled sheets into the trash in his driveway when Iwaizumi appears. Oikawa is groggy, but his friend’s presence hits him like a particular strong scent-memory, like wet leaves in October or summer rain on warm slate or Salonpas before a match. Oikawa jerks around and nearly knocks the garbage can over.

He’s just as irresistible as he was several days ago. He’s an Alpha and he should be setting off Oikawa’s instincts. And he does, a little. Just not in a territorial way. In the way he always has.

He smells... divine.

“Shittykawa,” Iwaizumi says as he jogs up to him with a slight grin, but then his face goes a little blank.

“Aw, Iwa-chan gimme a break,” Oikawa whines, ignoring whatever look is transforming his friend’s… stupidly handsome face. Just like his scent, he is as appealing as he was when he’d screamed himself hoarse watching a horror flick with Oikawa and Hanamaki at the movies last week. When he’d bought Oikawa ramen at their favorite spot after school three weeks ago. He’s wearing track pants and one of those long-sleeved athletic tees that shows off his arms, bigger since his Alpha hormones settled in. Those shiny black sneakers Oikawa picked out for him when they went to Tokyo together to visit his older brother. His backpack with the godzilla keychain Oikawa won for him at the arcade just a week before he presented. “I’m barely recovered from my first heat; I’m delicate!”

The surprisingly truthful words ring between them as Iwaizumi looks down at the ground. He’s not supposed to be around Oikawa yet, especially if he doesn’t know his presentation.

When he looks up again, eyes darting over Oikawa’s face, he says, “You’re an Alpha, too.”

Oikawa can’t look away from him, can’t look at anything but his reddening cheeks. “Yeah,” he replies. When nothing else falls from his mouth, Oikawa knows _both_ their faces are red.

Then, Iwaizumi laughs.

It’s a choked thing. He’s not one to laugh unnecessarily, but when he does it sounds endearingly out of use. “I, uh,” he begins, rubbing at the back of his head, and Oikawa’s eyes zoom to his wrist where it brushes his ear. “So this is kind of—I got you something, but I… made an assumption, uhm.”

Despite himself, Oikawa perks up. Alphas aren’t supposed to preen at things like gifts, they’re _providers_ , they’re strong and stoic.

Oikawa is greedy.

“You got me a gift,” Oikawa chirps, and moves forward. “Iwa-chan, you shouldn't have!”

Iwaizumi’s laugh goes wrong halfway through, lop-sided and nervous. “I—I… You won’t want it,” he tries.

Oikawa steps closers and tugs on his backpack. He needles him with, “Gimme, gimme, gimme.” Chants it until Iwaizumi’s face goes purple.

“Stop, stop—”

“Gimme,” Oikawa insists.

“Fine! Okay—Oikawa, keep it down, you’re so obnoxious—”

“Gimme!”

Their arms brush when Iwaizumi reaches around for the zip on his backpack, and the contact makes Oikawa break out in a sweat.

Surprised, he quiets as his friend, after looking up and down the street for possible onlookers, pulls a glossy magazine from his bag.

 _B I T E_ is emblazoned across the top of the cover, under which lies a very muscled, oiled and very nearly _naked_ Alpha. The man smolders up at Oikawa with dark eyes and darker hair. His chest is huge and his posture dominant, his abs are like bulging, rocky terrain down his stomach, and the shorts he’s wearing are tiny and bulging even more. Oikawa’s eyes catch on the thick outline of the Alpha’s dick under dark blue fabric between monstrous thighs. He looks ready to pounce on his unsuspecting viewer.

Oikawa looks up at Iwaizumi before clearing his throat.

“I was gonna say, uh—congrats on becoming an… Omega,” Iwaizumi husks out as Oikawa turns through the first couple pages, filled with other Alphas, “but I guess that was a little... I dunno what I was thinking. I’m an idiot.”

The whole magazine mirrors the cover closely, but… less clothed, and with the occasional, waifish Omega looking blissed out beneath their possessive partner.

“You probably don’t want this at all. It’s weird right?” Iwaizumi continues, and he reaches to pull it from his hands, Oikawa snatches it away.

“Thank you, Iwa-chan,” he says, and then, before he can think twice, he crowds into Iwaizumi’s space and wraps him in a hug.

Iwaizumi grunts softly at the sudden expulsion of air from his lungs, but stays stock still as Oikawa, quick and just as breathless as his friend, hides in his neck and nuzzles under his ear, eyes fluttering closed as Iwaizumi’s strong, familiar, knee-buckling scent envelopes him.

He ducks away quickly and says his thank yous and goodbyes so quickly he barely registers Iwaizumi is as flustered as he is when Oikawa rushes back inside, magazine stuffed under his shirt so his parents don’t see.

When Oikawa opens the magazine again that night, he knots and comes like a hair-trigger the moment he’s got his fist around his dick. Coming so quick within the first month of presentation is normal. But, it may be the only normal thing about Oikawa’s situation.

It’s not until they see each other again, after a medically-mandated week off for Oikawa (where he wore his new magazine out several times over) and after several awkward phone calls—

“How are you feeling?” Iwaizumi’s voice buzzes through the phone as Oikawa curls on his bedroom floor, tired of the softness of his bed, tired of the stench of it and the barely-there relief he’s had while his hormones bounce around like pinballs and drive him wild, even though he’s past his true heat.

Oikawa tries not to think of the moment he’d humped the stuffing out of his pillow and says, “I’m fucking sore as hell.”

Iwaizumi’s funny laugh is even more endearing in the quiet crackle over the phone.

“But it feels so good,” Oikawa says, legs pressing together. He wonders what his friend his thinking on the other end. “How do you _stop_ , Iwa-chan?”

The laugh turns into a choked breath and Iwaizumi doesn’t speak for a while.

—and somewhat… tense text messages—

 **Oikawa:** i just need a hole kill meeeee  
**Oikawa:** was it this bad 4 u?  
**Oikawa:** do u ever pop ur knot like… on a breeze i s2g theres jizz everywhere

 **Iwa-chan:** Don’t text me things like that. You’re so gross!

 **Oikawa:** does it get any better tho? im soooo hard all the time

 **Iwa-chan:** Stop.

 **Oikawa:** everything gets me off  
**Oikawa:** even your magazine i’m dying

 **Iwa-chan:** Tooru please

—that Oikawa starts to wonder what his Iwa-chan had been doing, giving him a gift like that. Friends don’t give each other gifts when they present. Not _things like that_ , at least.

What was he thinking when he’d heard Oikawa was suffering through his first heat? He’d thought Oikawa would be an Omega, or… or maybe he _hoped_ he would. Was he wondering what it would be like for them, after? An Alpha and Omega, as best friends? Was he hoping Oikawa would look at the Alphas in the magazine and see Iwaizumi’s eyes staring back?

Oikawa doesn’t figure out the answer until several months later.

Well, ‘figure it out’ is generous, because he pretty much stumbles into it, clever as he knows he is.

They’re studying in Iwaizumi’s room on a Thursday afternoon after a cancelled practice. Iwaizumi’s father is working, because he’s always working, and Iwaizumi’s mother is at her book club. So Oikawa studies with Iwaizumi alone. Unsupervised, because why would they need it, being Alphas?

Iwaizumi sits in his ratty old sweatpants with their junior high school’s name emblazoned up his left leg. It only fits because he refused to get the right size when he was thirteen, but it fits _just barely_ now. The elastic hem of the right ankle is frayed and ripped and hiked up his calf, revealing his bony ankle as he taps his foot idly to the soft music playing on his clock radio. He’s resting his head on his arm, his t-shirt stretching with the pull of his muscle. He’s chewing on his pen, frowning up at the novel they’re reading in their lit class. Further up, his thighs splay distractingly and the soft blue fabric pulls _tight_ around them as his eyes droop like he could fall asleep between one breath and the next. His stomach peeks out from his ridden up shirt and Oikawa gives up on writing his analysis of Chapter Six’s dialogue because it’s just too much work, and his glasses are sliding down his nose, too loose again, and he can feel his dick filling against his thigh. It presses uncomfortably against the tatami mat as his hip presses almost unconsciously against Iwaizumi’s sprawled thigh.

He sighs loudly, because maybe his chatter and noise will divert Iwa-chan’s attention and they won’t have to go through another awkward week when he gets mad and flustered and tells Oikawa to stop being so weird.

“I can’t concentrate,” Oikawa despairs. He stretches his arms out until he’s lying flat next to his friend. He watches him read quietly for a while as his eyelids dip low again.

Iwaizumi tosses his book to the side and rolls toward him a little after a moment, sleepy-limbed. Oikawa breathes carefully when Iwaizumi slides his arm over his back and curls one knee over the back of Oikawa’s so his front is pressed to Oikawa’s side. Just like when they were little kids.

Just like when nothing mattered but each other.

Then, almost as if on accident, Iwaizumi noses into Oikawa’s neck and takes a deep, luxurious breath.

“Iwa—”

Oikawa is hard in moments, but Iwaizumi—Iwaizumi _moans_ , mouth opening and teeth nearly grazing the tendon just under Oikawa’s skin when he catches the sudden change in scent. A second later, Oikawa registers that he’s rock hard against his side, rubbing in one slow rotation against his ass through his jeans and hand clenching into Oikawa’s cardigan over his ribs.

Oikawa snaps.

He turns so quickly in Iwaizumi’s embrace the guy looks dazed—or maybe that’s the flaring heat of Oikawa’s arousal, and the visible evidence of it at the crotch of his jeans. Oikawa ignores his look of surprise and pulls him down on top of him, but not before unbuckling his pants and shoving at Iwaizumi’s.

“Ah—Tooru!” Iwaizumi gasps when Oikawa finally, _finally_ touches him. Rubs at his tightening balls and runs his fingers over his clenching thighs. Relishes the feeling of his knot not yet swollen at the base of his dick. He matches Oikawa in length but he’s thicker, just like the rest of his perfect body, and it makes Oikawa’s mouth water because he’s better than all those Alphas Oikawa has knotted over, since he gave him that magazine months ago. Oikawa wrings him up and down and watches his shocked face crumple into a rictus of pleasure.

“Iwa-chan, you’re so hard already,” Oikawa says in amazement.

“Y-you caught me off guard,” Iwaizumi argues.

“ _I_ caught you? You nearly bit me!” Oikawa cries, and he shoves at him, knocking off his glasses as he knocks Iwaizumi onto his back with his own Alpha strength.

The posturing doesn’t seem to deter Iwaizumi or his hard-on, thicker and leaking precome steadily as he fills nearly to his full length. The base of his dick is ruddy and dark, looks bruised and sore as his knot grows harder without direct stimulation, and Oikawa _knows_ what that feels like. He can feel it himself! Iwaizumi just moans, voice crackling as Oikawa kicks off his jeans and underwear and straddles him, using their combined precome to slot their dicks together and rub one out for the both of them.

“Tooru,” Iwaizumi says. “ _Tooru._ ”

Oikawa thinks about all the times he’s imagined his Iwa-chan saying that, _like that_ as he fucked his fist or pressed fingers into himself. He crows inwardly that it’s coming true, and hopes it’s not the first time Iwaizumi has imagined this, either.

His fingers are slick and wet now, so he makes sure Iwaizumi has his eyes open when he moves his hands away and reaches behind himself.

“Tooru—” Iwaizumi hisses as Oikawa’s eyes falls closed, slotting two fingers into himself impatiently. They both can smell his scent change with a little pain, and a whole lot of desperation.

“Say it again,” Oikawa demands.

“Tooru,” he says as they rut against each other and Oikawa shoves back onto his own fingers until he’s almost _willed_ himself loose. “Tooru, you’re— _oh!_ ”

Iwaizumi is so hard, so slick from his arousal that even with the burning stretch, he slips into Oikawa almost easily when Oikawa kneels up and screws down onto him, onto his best friend.

Iwaizumi goes rigidly still, and then suddenly his big hands grab Oikawa’s hips harshly, he jams his heels into the tatami, and he fucks up into him. Oikawa loses his grip from the first thrust, slippery hands scrabbling at Iwaizumi’s flexing arms until he’s hunched over him, knocking his forehead against his as Iwaizumi ruts into him, fast.

“Iwa—Iwa-chan,” Oikawa moans. “I wanted this. I think about this all the time, think about you.”

Iwaizumi’s fingernails bite into the meat of Oikawa’s ass. Their scents are so intermingled that Oikawa might go insane with satisfaction.

“Wanted you to be my first, before,” he continues, babbling.

Iwaizumi whines and his legs shake and he loses his footing and Oikawa slams down onto his dick as Iwaizumi’s ass hits the carpet.

“Tooru,” he huffs out, his knot starting to stretch painfully at Oikawa’s hole.

Oikawa rolls his hips frantically, sticky fingers reaching down between them to tease at his knot, aching under his skin.

“Wanted you more, after,” Oikawa continues, voice falling apart as his pleasure climbs higher, barrelling past the pleasure, the pain of his first few heats and the disatisfaction they brought, and shooting toward pure euphoria. “ _Hajime._ ”

“Wanna be your Alpha,” Iwaizumi chokes out, and the sound of his voice is hurt. It hurts. “Still,” he adds on a tortured roll of his hips.

“Wanna be yours,” Oikawa returns.

Iwaizumi seizes up, shudders out tiny little breaths as pain sears around Oikawa’s hole. He feels the stretch of Iwaizumi’s knot filling him and catching at his rim, keeping him plugged up as his Iwa-chan’s eyes roll back in his head and he comes heavily, sheathed inside.

Oikawa’s own orgasm wrenches from him violently like one of Iwaizumi’s spikes and his knot pops so suddenly he clenches around Iwaizumi as come stripes up Iwaizumi’s soft t-shirt and catches on his collarbone. Iwaizumi wails pitifully, legs shaking as Oikawa squeezes his already sensitive knot, provoking another, smaller orgasm.

Oikawa squeezes tight below his knot and just barely holds himself up on one hand. It doesn’t last long, and they slowly topple over like a demolished building does, crumbling from the bottom-up until they lie tangled in a heap, still tied together, whimpering.

“Tooru,” Iwa-chan says weakly, when he’s able to speak again, and Oikawa’s eyes close as he lingers in the euphoria of his orgasm.

Callused fingers slip under his around his knot, and if he hadn’t come his brains out, he would have come again just like Iwaizumi. He jerks a little in Iwa-chan’s arms, and somehow his friend has it in him to laugh. That funny little laugh that always makes Oikawa warm with affection.

After an age, Iwaizumi’s knot softens enough to for Oikawa to slip off of him, stretching out his legs and breathing deliberately through the new, delicious aches they’ve created together. Iwa-chan’s hands shakes a little as he passes them up and down Oikawa’s back dipping under his cardigan and t-shirt to sweep over sweat-tacky skin and unknowingly soothing something deep inside Oikawa that his knot simply couldn’t. Oikawa nuzzles up under Iwaizumi’s chin and grazes his teeth against his Adam’s apple, lingers there where his scent is intoxicating. It mixes so well with his own scent that tears prick at Oikawa’s eyes.

“Why can’t we belong to each other?” he asks eventually, trying and failing to keep the water from his voice.

Iwaizumi passes a hand over his hair and tilts his head back until he can look down into his eyes. He smiles a little.

“I think maybe we always have,” he says.

“Ooh, so sentimental, Iwa-chan,” Oikawa coos.

Iwa-chan laughs again, and Oikawa has to kiss it from his lips.

**Author's Note:**

> Thank you for reading! Comments & kudos are appreciated. :)
> 
> Come say hi on [Tumblr](http://byesweetheart.tumblr.com/) or [Twitter](https://twitter.com/byesweetheart_)!


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